Glucose-6-phosphate dehydrogenase (Glc6PD) from the bacterium Leuconostoc mesenteroides has commercial utility in the enzymatic oxidation of glucose 6 phosphate. This enzyme is capable of utilizing either NAD.sup.+ or NADP.sup.+ as a coenzyme, whereas Glc6PD from other conventional sources such as human erythrocytes or rat liver can utilize NADP.sup.+ but show little if any activity with NAD.sup.+. L. mesenteroides is employed in commercial enzyme immunoassay systems, clinical laboratory determinations such as glucose analysis, and other useful chemical reactions requiring the oxidation of glucose-6-phosphate.
Obtaining Glc6PD by standard enzyme purification methods in commercially practicable amounts has been expensive and difficult. Using recombinant DNA technology, it is possible to produce enzymes such as Glc6PD economically and in large amounts with bacteria such as E. coli. Various techniques of gene cloning are known to the art, and others have succeeded in cloning genes for Glc6PD from sources such as Drosophila melanogaster, rat liver, and human erythrocytes, the Glc6PD resulting from such genes lacks the desirable properties of that from Leuconostoc mesenteroides. Until applicant's invention, it is believed, that no one has successfully cloned the Glc6PD gene from Leuconostoc mesenteroides. A purported cloning of the L. mesenteroides gene was published by Murphy et al. (J. Bacteriology, Vol. 169, pp 334-339, June 1987).